Frost damage to the flowers and early developing fruits is one of the most limiting factors in the most almond cultivation regions of the world. This study was undertaken to help understand almond response to frost spring at same phenological stage, in order to develop criteria for the selection of cultivars with improved resistance to frost on the basis of field and laboratory experiments. In general, in this study, K-12-6, Ferragnes, Tuono and K-16-25 were negatively affected by frost at same popcorn and flowering stages in field test and laboratory constitutions. Experiment laboratory test showed, the four cultivar and selection suffering a greater frost damage rate at flowering at- 3.2° C ( 100%, 100%, 58 and 45% for K-12-6 , Ferragnes, Tuono and K-16-25 respectively) compared with the balloon stage at- 6.40C (100%,100%,85% and 58% for K-12-6 , Ferragnes, Tuono and K-16-25 respectively). Up to -3.1° C there was no damage at the balloon stage, where as in anthesis there was strict damage in four late flowering almond cultivars and selections at -3.2° C. Also, Results showed that the severity of frost damage was influenced by genotypes of almond. Genotypes that had the more resistant to frost damage had higher amount proline content. It is suggested that the content proline may serve as indicator of frost tolerance in almond breeding material.